How to Kill Gnats in Drains

Gnats appearing around your sinks, showers, or drains can quickly shift from a mild irritation to an extreme, recurring, and unsanitary issue.

Many homeowners first notice small insects flying around the bathroom or hovering near the sink and wonder if they're fruit flies, sewer flies, or something else entirely.

In reality, these pests are often bathroom flies—also known as drain gnats or drain flies.

Because these insects thrive in moist, bacteria-rich environments, they reproduce rapidly and infestations become frequent, damaging, and difficult to manage without proper treatment. If you've ever wondered what do drain gnats look like? or why you suddenly see flies in drain openings, understanding their behavior is the first step toward getting rid of them for good.

How to Get Rid of Gnats in Drains

If you've recently heard buzzing near your sink or spotted tiny winged insects hovering in the bathroom or kitchen, you're likely dealing with bathroom flies—a common name used for drain gnats. These pests multiply quickly and can spread throughout your home if not addressed early.

Many people struggle to identify these pests and ask, what do drain gnats look like?

What Are Gnats?

Drain gnats—also known as drain flies, fungus gnats, bathroom flies, or moth flies—are winged insects that live and breed inside the organic buildup of your drain pipes. Once a few appear, it doesn't take long for them to multiply and cause a serious infestation.

What Do Drain Gnats Look Like?

If you're trying to identify them, here's what drain gnats look like:

• Small (1–3 mm)
• Fuzzy, moth-like bodies
• Rounded wings
• Slow, erratic flight pattern

Once you know what drain gnats look like, you'll easily distinguish them from fruit flies or other small insects. Their fuzzy appearance is one of the biggest clues. If you see clusters of tiny flies in drain openings or hovering around sinks, chances are you're dealing with drain gnats.

Why Drain Gnat Infestations Become Extreme

Drain gnats thrive in areas rich with moisture and bacteria. Your drains provide everything they need:

• Water
• Shelter
• Organic sludge to feed on
• Places to lay eggs

A single female drain fly can lay up to 200 eggs at once. That's why bathroom flies often become a frequent and severe problem if the underlying cause – buildup inside your pipes – isn't addressed.

Getting Rid of Gnats in Drains

1. Clean Your Drain Thoroughly

Drain gnats live inside the slime layer lining your pipes, so surface cleaning will never fully eliminate them. The following methods target the actual breeding source:

Hydrogen Peroxide

Pour ½ cup of hydrogen peroxide down the drain. This helps kill larvae, break down bacterial buildup, and reduce odors that attract bathroom flies. The bubbling you see means it's working.

Boiling Water

One of the simplest treatments:

1. Boil water.
2. Pour it slowly down the drain in 3–4 stages.
3. Wait 10–15 seconds between each pour.

This helps wash away larvae and loosen buildup contributing to flies in drain areas.

Baking Soda, Salt & Vinegar Treatment

A natural, effective solution. How to apply it:

1. Add ½ cup baking soda to the drain.
2. Follow with ½ cup salt.
3. Pour in 1 cup white vinegar.
4. Let it foam for several hours or overnight.
5. Flush with hot water.

This method breaks down sludge, reduces odors, and makes it harder for bathroom flies to return.

Chemical Cleaners

For severe infestations, a product like Drano can break down heavy buildup as chemical cleaners kill larvae deep inside pipes, remove slime layers, and clear minor clogs.

This said, be sure to use this sparingly, especially in older plumbing systems.

2. Use Traps to Catch Remaining Gnats

Cleaning removes the breeding ground, but you'll still need to eliminate adult gnats flying around your home.

Apple Cider Vinegar Trap

1. Pour 1 inch of apple cider vinegar into a small container.
2. Add a few drops of dish soap.
3. Cover with plastic wrap.
4. Poke tiny holes in the top.

This combination attracts and traps bathroom flies effectively.

Other Trap Options

• Sticky traps around the sink
• UV gnat traps
• Store-bought drain fly traps

These help reduce the number of adult flies in drain areas that manage to escape initial treatments.

3. Be Proactive

Prevent future infestations by adopting healthy drain habits.

Keep Drains Clean

Flush drains weekly with boiling water or baking soda and vinegar.

Avoid Putting Food Waste Down Your Drains

Food scraps contribute to the organic film that drain gnats feed on.

Fix Plumbing Problems Early

Addressing slow drains, avoiding clogs, and leaks create moisture-rich environments where bathroom flies thrive.

Keep Sink Areas Dry

Even small puddles attract gnats. Wipe surfaces often to remove excess moisture.

When to Contact a Professional Plumber

If you're still seeing bathroom flies around sinks, persistent flies in drain openings, and recurring infestations despite cleaning, it might be time to contact a professional plumber.

Severe infestations often mean hidden buildup deeper inside the plumbing, issues in the sewer line, and damaged pipes creating ideal breeding sites.

Professional plumbers have specialized tools to thoroughly remove sludge, inspect pipes, and eliminate gnats at the source. This is the most reliable way to ensure the infestation doesn't return.

Restore Clean, Gnat-Free Drains — Call J. Blanton Plumbing

If you're tired of dealing with bathroom flies, flies in drain pipes, or persistent gnat infestations, J. Blanton Plumbing can help.

We provide complete drain cleaning, eliminate drain fly infestations and offer preventative solutions for long-term protection. Schedule your professional drain service today and take back your home from drain gnats!